Black Mulch Ingredients

Mulch is any material used to prevent weed growth and to retain soil moisture, be it shredded wood, straw, leaves or a man-made material such as shredded tires. Black mulch is designed to give your landscaping a certain look of contrast. However, whatever mulch you put on your lawn and garden will break down and contribute to the make-up of your soil. For this reason, black mulch may include ingredients that some gardeners might want to avoid.

Hardwood and Dye

Black wood mulches are generally made of shredded hardwood that is dyed black. Commonly used dyes are similar to water based paints or are natural vegetable dyes. Black mulch dyes may also include preservatives and chemical binders to assist the coloring of the wood chips. Dyes to avoid are the possibly carcinogenic dyes made by the incomplete combustion of petroleum products. Ask your mulch vendor for verification. Meanwhile, the wood of your mulch comes from shredded waste wood which may have been chemically treated. Another consideration is that wood needs nitrogen to break down, consequently leaching the nitrogen from the soil that your plants need for food.

Rubber

Black rubber mulch is made from shredded tires. While this is a popular choice for playgrounds, reconsider using tire mulch on your lawn and garden. Black rubber mulch will leak pollutants as it breaks down and will smell toxic when the summer sun warms it up.

Compost

Black composted mulch is a healthy solution. Compost, whether you buy it or make your own, is naturally dark in color due to the rich nutrients it contains. Additionally, as the compost breaks down, your lawn and garden will benefit from the natural plant food contained in the mulch. Compost requires frequent replenishment, however, and as such is not as durable as rubber or dyed wood mulch.

Lava Rock

Black lava rock is another completely natural mulch that will not harm your plants as it breaks down into lava sand. While lava sand will not add nutrients to your soil, the sand will help your soil retain moisture. As with any mulch, do not place mulch directly against your growing plants to ensure the plants are not damaged by the mulch.